Coaxial connectors have been developed for use in high frequency environments of 18 GHz or more. The inner conductors of two connectors can be connected in a simple pin-and-socket connection. The outer conductors are preferably connected in a butt configuration, wherein the extreme outer ends of the two connectors abut each other, as this results in a constant inside diameter between connectors. However, if a butt connection is used, care must be taken to assure that the two outer contacts are always electrically connected together, and that there is substantially no gap at their interface. Gaps can be eliminated by floating one of the outer conductors so it is resiliently pressed against the other outer conductor, but such floating adds complication. U.S. Pat. No. 4,358,174 shows a slide-on coaxial connection arrangement with an abutment of outer conductors, but which is relatively complex. If a pair of coaxial connectors could be mated without the need for precise abutting of outer contacts, but without substantial losses, then the connectors could be constructed more compactly and at lower cost. It would be desirable if such connectors could be mated by sliding one into the other, so that a compact array of first and second connectors could be easily mated.